The MCP standard gave rise to dreams of interconnected agents and nightmares of what those interconnected agents would do with unfettered access to APIs, data, and local systems. Aaron Parecki explains how OAuth's new Client ID Metadata Documents spec provides more security for MCPs and the reasons why the behavior and design of MCPs required a new spec like this.

Segment resources:

• https://aaronparecki.com/2025/11/25/1/mcp-authorization-spec-update
• https://www.ietf.org/archive/id/draft-ietf-oauth-client-id-metadata-document-00.html
• https://oauth.net/cross-app-access/
• https://oauth.net/2/oauth-best-practice/

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Show Notes: https://securityweekly.com/asw-360